//
//  main.cpp
//  ex5_21
//
//  Created by baili on 2024/6/1.
//
using namespace std;
#include <iostream>

int main(int argc, const char * argv[]) {
    // insert code here...
    std::cout << "Hello, World!\n";
    char s[100];
    cout<< "请输入一个字符串："<<endl;
    cin >> s;
    int i,n,flag =1;
    n = strlen(s);
    for (i =0; i<n/2; i++) {
        if (s[i]!=s[n-i-1]) {
            
            flag = 0;
            break;
        }
    }
    if (flag==1) {
        cout<< "YES："<<endl;
    }else{
        cout<< "NO："<<endl;
    }
    return 0;
}
